Catheter with Stretchable Irrigation Tube

ABSTRACT

In one embodiment, a medical system includes a catheter configured to be inserted into a body part of a living subject, and including a deflectable element having a distal end, an expandable distal end assembly disposed at the distal end of the deflectable element, and comprising a plurality of electrodes, a distal portion, and a proximal portion, and configured to expand from a collapsed form to an expanded deployed form, and a stretchable irrigation tube disposed between the distal portion and the proximal portion, and comprising a plurality of irrigation holes, and configured to stretch longitudinally when the distal end assembly is collapsed from the expanded deployed form to the collapsed form.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of U.S. patentapplication Ser. No. 16/863,980 filed Apr. 30, 2020, the entire contentsof which is incorporated herein by reference as if fully set forthbelow.

FIELD OF THE INVENTION

The present invention relates to medical devices, and in particular, butnot exclusively to, catheters.

BACKGROUND

A wide range of medical procedures involve placing probes, such ascatheters, within a patient's body. Location sensing systems have beendeveloped for tracking such probes. Magnetic location sensing is one ofthe methods known in the art. In magnetic location sensing, magneticfield generators are typically placed at known locations external to thepatient. A magnetic field sensor within the distal end of the probegenerates electrical signals in response to these magnetic fields, whichare processed to determine the coordinate locations of the distal end ofthe probe. These methods and systems are described in U.S. Pat. Nos.5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, inPCT International Publication No. WO 1996/005768, and in U.S. PatentApplication Publications Nos. 2002/0065455, issued as U.S. Pat. No.6,690,963 on Feb. 10, 2004, and 2003/0120150 issued as U.S. Pat. No.7,729,742 on Jun. 1, 2010, and 2004/0068178, now abandoned. Locationsmay also be tracked using impedance or current based systems.

One medical procedure in which these types of probes or catheters haveproved extremely useful is in the treatment of cardiac arrhythmiasCardiac arrhythmias and atrial fibrillation in particular, persist ascommon and dangerous medical ailments, especially in the agingpopulation.

Diagnosis and treatment of cardiac arrhythmias include mapping theelectrical properties of heart tissue, especially the endocardium, andselectively ablating cardiac tissue by application of energy. Suchablation can cease or modify the propagation of unwanted electricalsignals from one portion of the heart to another. The ablation processdestroys the unwanted electrical pathways by formation of non-conductinglesions. Various energy delivery modalities have been disclosed forforming lesions, and include use of microwave, laser and more commonly,radiofrequency energies to create conduction blocks along the cardiactissue wall. In a two-step procedure, mapping followed by ablation,electrical activity at points within the heart is typically sensed andmeasured by advancing a catheter containing one or more electricalsensors into the heart, and acquiring data at a multiplicity of points.These data are then utilized to select the endocardial target areas atwhich the ablation is to be performed.

Electrode catheters have been in common use in medical practice for manyyears. They are used to stimulate and map electrical activity in theheart and to ablate sites of aberrant electrical activity. In use, theelectrode catheter is inserted into a major vein or artery, e.g.,femoral vein, and then guided into the chamber of the heart of concern.A typical ablation procedure involves the insertion of a catheter havinga one or more electrodes at its distal end into a heart chamber. Areference electrode may be provided, generally taped to the skin of thepatient or by means of a second catheter that is positioned in or nearthe heart. RF (radio frequency) current is applied through the tipelectrode(s) of the ablating catheter, and current flows through themedia that surrounds it, i.e., blood and tissue, between the tipelectrode(s) and an indifferent electrode. The distribution of currentdepends on the amount of electrode surface in contact with the tissue ascompared to blood, which has a higher conductivity than the tissue.Heating of the tissue occurs due to its electrical resistance. Thetissue is heated sufficiently to cause cellular destruction in thecardiac tissue resulting in formation of a lesion within the cardiactissue which is electrically non-conductive.

US Patent Publication 2019/0117301 of Steinke, et al., issued as U.S.Pat. No. 11,382,688 on Jul. 12, 2022, describes a catheter and cathetersystem for treatment of a blood vessel of a patient include an elongateflexible catheter body with a radially expandable structure. A pluralityof electrodes or other electrosurgical energy delivery surfaces canradially engage material to be treated when the structure expands. Amaterial detector near the distal end of the catheter body may measurecircumferential material distribution, and a power source selectivelyenergizes the electrodes to eccentrically treat of a body lumen.

U.S. Pat. No. 9,757,180 to Gelfand, et al., describes systems, devices,and methods for treating a patient having a sympathetically mediateddisease associated at least in part with augmented peripheralchemoreflex or heightened sympathetic activation. The treatments includeablating one or more peripheral chemoreceptors or associated afferentnerves to reduce or remove afferent neural signals from the peripheralchemoreceptor.

U.S. Pat. No. 9,474,486 to Eliason, et al., describes anelectrophysiology catheter. In one embodiment, the catheter includes anelongated, deformable shaft having a proximal end and a distal end and abasket electrode assembly coupled to the distal end of the shaft. Thebasket electrode assembly has a proximal end and a distal end and isconfigured to assume a compressed state and an expanded state. Theelectrode assembly further includes one or more tubular splines having aplurality of electrodes disposed thereon and a plurality of conductors.Each of the plurality of conductors extends through the tubular splinefrom a corresponding one of the plurality of electrodes to the proximalend of the basket electrode assembly. The tubular splines are configuredto assume a non-planar (e.g., a twisted or helical) shape in theexpanded state.

International Patent Publication WO 2019/074733 of St. Jude MedicalCardiology Div. Inc. describes high-density mapping catheters with anarray of mapping electrodes. These catheters can be used for diagnosingand treating cardiac arrhythmias, for example. The catheters are adaptedto contact tissue and comprise a flexible framework including theelectrode array. The array of electrodes may be formed from a pluralityof columns of longitudinally-aligned and rows of laterally-alignedelectrodes.

U.S. Pat. No. 10,362,952 to Basu, et al., describes a catheter fordiagnosing and ablating tissue that has a stabilized spine electrodeassembly. The stabilized spine electrode assembly has at least twospines secured to the catheter body at their proximal ends and at leastone tether, secured between locations distal of the proximal ends ofadjacent spines. The spines have a collapsed arrangement in which thespines are arranged generally along a longitudinal axis of the catheterbody and an expanded arrangement in which at least a portion of eachspine bows radially outwards from the longitudinal axis and the at leastone tether exerts tension on the adjacent spines.

SUMMARY OF THE INVENTION

There is provided in accordance with an embodiment of the presentdisclosure, a medical system including a catheter configured to beinserted into a body part of a living subject, and including adeflectable element having a distal end, an expandable distal endassembly disposed at the distal end of the deflectable element, andincluding a plurality of electrodes, a distal portion, and a proximalportion, and configured to expand from a collapsed form to an expandeddeployed form, and a stretchable irrigation tube disposed between thedistal portion and the proximal portion, and including a plurality ofirrigation holes, and configured to stretch longitudinally when thedistal end assembly is collapsed from the expanded deployed form to thecollapsed form.

Further in accordance with an embodiment of the present disclosure theirrigation holes are disposed radially around the irrigation tube.

Still further in accordance with an embodiment of the present disclosurethe irrigation holes are disposed longitudinally along the irrigationtube.

Additionally, in accordance with an embodiment of the present disclosurethe irrigation holes are disposed longitudinally along the irrigationtube.

Moreover in accordance with an embodiment of the present disclosure, thesystem includes an ablation power generator configured to be connectedto the catheter, and apply an electrical signal to the electrodes, anirrigation reservoir configured to store irrigation fluid, and a pumpconfigured to be connected to the irrigation reservoir and the catheter,and to pump the irrigation fluid from the irrigation reservoir throughthe irrigation holes of the irrigation tube.

Further in accordance with an embodiment of the present disclosure arelaxed state of the distal end assembly is the expanded deployed form,the distal end assembly being configured to collapse into the collapsedform when the catheter is retracted in a sheath.

Still further in accordance with an embodiment of the present disclosurea relaxed state of the distal end assembly is the collapsed form, thesystem further including a puller element disposed inside thedeflectable element and the stretchable irrigation tube, and connectedto the distal portion of the distal end assembly, and configured whenpulled to expand the distal end assembly from the collapsed form to theexpanded deployed form.

Additionally, in accordance with an embodiment of the present disclosurethe distal end assembly includes a basket assembly.

Moreover, in accordance with an embodiment of the present disclosure thebasket assembly includes a plurality of splines.

Further in accordance with an embodiment of the present disclosure thesplines include Nitinol.

Still further in accordance with an embodiment of the present disclosurethe stretchable irrigation tube includes a biocompatible stretchablematerial.

Additionally, in accordance with an embodiment of the present disclosurethe holes include laser drilled holes.

Moreover, in accordance with an embodiment of the present disclosure thebiocompatible stretchable material includes Polyether block amide(PEBA).

Further in accordance with an embodiment of the present disclosure thebiocompatible stretchable material is a porous material that includespores forming at least some of the holes.

Still further in accordance with an embodiment of the present disclosurethe biocompatible stretchable material includes expandedPolytetrafluoroethylene (ePTFE).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood from the following detaileddescription, taken in conjunction with the drawings in which:

FIG. 1 is a schematic view of a medical system constructed and operativein accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of a catheter in a collapsed form constructedand operative in accordance with an embodiment of the present invention;

FIG. 3 is a schematic view of the catheter of FIG. 2 in a deployed form;

FIG. 4 is a cross-sectional view of the catheter of FIG. 3 along lineA:A;

FIG. 5 is a more detailed cross-sectional view of the catheter insideblock A of FIG. 4 ;

FIG. 6 is a more detailed cross-sectional view of the catheter insideblock B of FIG. 4 ;

FIG. 7A is a schematic view of a catheter in a collapsed formconstructed and operative in accordance with an alternative embodimentof the present invention; and

FIG. 7B is a schematic view of the catheter of FIG. 7A in a deployedform.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

Irrigation is commonly used with catheters to provide cooling duringmedical procedures such as radio-frequency (RF) ablation, for example.One solution for providing irrigation in a basket-type catheter is tohave an irrigation channel run through the catheter which terminates inthe middle of the basket. Irrigation fluid may then be pumped throughthe irrigation channel to the distal end of the irrigation channel wherethe irrigation fluid exits and provides cooling to tissue in the regionof the basket as well as diluting blood locally. However, the irrigationis not very well directed and although it may be sufficient forelectroporation, which does not generate much heat, it is generally notsufficient to reduce heat created during RF ablation. An additionalproblem encountered with basket catheters is that the basket needs to bein a collapsed or semi-collapsed form during insertion into the body andthen deployed to its expanded form in a body cavity. The requirement tobe able to collapse and expand the basket adds further complications toproviding effective irrigation as an irrigation channel may interferewith the expansion and collapsing of the basket.

Embodiments of the present invention, provide a catheter with anexpandable distal end assembly (such as a basket) including electrodesthereon, with a stretchable irrigation tube fixed between a proximal anddistal end of the assembly. The irrigation tube includes holes aroundthe tube to direct irrigation fluid in different directions to provideeffective irrigation and cooling. Using a stretchable tube allows theirrigation tube (and therefore the irrigation holes) to extend from theproximal to the distal end of the assembly as the tube stretches andrelaxes according to the form of the assembly so that when the assemblyis collapsed, the tube is stretched, and when the assembly is expanded,the tube relaxes.

In some embodiments, the holes are disposed along the length of the tubeand around the circumference of the tube to provide a much more uniformirrigation spray throughout the distal end assembly. The tube may bemade formed from any suitable biocompatible stretchable material, suchas Polyether block amide (PEBA) (e.g., PEBAX (with a shore D durometerbetween 25 and 72)), or a stretchable Polyurethane, a silicone polymer,or expanded Polytetrafluoroethylene (ePTFE). Holes may be made in thetube using any suitable method for example, but not limited to, laserdrilling. Some materials such as ePTFE may include pores which areformed when the material is pre-stretched or electrospun. The pores maythen provide the irrigation holes in the irrigation tube. When the holesare numerous enough (e.g., with a porous tubes), the irrigation fluidmay weep from the tube instead of being sprayed. Nevertheless, providingirrigation via weeping provides sufficient irrigation in manyapplications.

In some embodiments, the distal end assembly is collapsed by beingretracted into a catheter sheath. In other embodiments, the distal endassembly has a naturally collapsed form and pulling a puller wire causesthe distal end assembly to expand. The puller wire may be disposed inthe stretchable irrigation tube and is connected to the distal end ofthe distal end assembly.

System Description

Reference is now made to FIG. 1 , which is a schematic view of a medicalsystem 20 constructed and operative in accordance with an embodiment ofthe present invention. The system 20 includes a catheter 40 configuredto be inserted into a body part of a living subject (e.g., a patient28). A physician 30 navigates the catheter 40 (for example, a basketcatheter produced Biosense Webster, Inc. of Irvine, Calif., USA), to atarget location in a heart 26 of the patient 28, by manipulating anelongated deflectable element 22 of the catheter 40, using a manipulator32 near a proximal end of the catheter 40, and/or deflection from asheath 23. In the pictured embodiment, physician 30 uses catheter 40 toperform electro-anatomical mapping of a cardiac chamber and ablation ofcardiac tissue.

Catheter 40 includes an expandable distal end assembly 35 (e.g., abasket assembly), which is inserted in a folded configuration, throughsheath 23, and only after the catheter 40 exits sheath 23 does thedistal end assembly 35 regain its intended functional shape. Bycontaining distal end assembly 35 in a folded configuration, sheath 23also serves to minimize vascular trauma on its way to the targetlocation.

Catheter 40 includes a plurality of electrodes 48 for sensing electricalactivity and/or applying ablation power to ablate tissue of the bodypart. Catheter 40 may incorporate a magnetic sensor (not shown) at thedistal edge of deflectable element 22 (i.e., at the proximal edge of thedistal end assembly 35). Typically, although not necessarily, themagnetic sensor is a Single-Axis Sensor (SAS). A second magnetic sensor(not shown) may be included at any suitable position on the assembly 35.The second magnetic sensor may be a Triple-Axis Sensor (TAS) or aDual-Axis Sensor (DAS), or a SAS by way of example only, based forexample on sizing considerations. The magnetic sensors and electrodes 48disposed on the assembly 35 are connected by wires running throughdeflectable element 22 to various driver circuitries in a console 24.

In some embodiments, system 20 comprises a magnetic-sensing sub-systemto estimate an ellipticity of the basket assembly 35 of catheter 40, aswell as its elongation/retraction state, inside a cardiac chamber ofheart 26 by estimating the elongation of the basket assembly 35 from thedistance between the magnetic sensors. Patient 28 is placed in amagnetic field generated by a pad containing one or more magnetic fieldgenerator coils 42, which are driven by a unit 43. The magnetic fieldsgenerated by coil(s) 42 transmit alternating magnetic fields into aregion where the body-part is located. The transmitted alternatingmagnetic fields generate signals in the magnetic sensors, which areindicative of position and/or direction. The generated signals aretransmitted to console 24 and become corresponding electrical inputs toprocessing circuitry 41.

The method of position and/or direction sensing using external magneticfields and magnetic sensors, is implemented in various medicalapplications, for example, in the CARTO® system, produced byBiosense-Webster, and is described in detail in U.S. Pat. Nos.5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, inPCT Patent Publication WO 96/05768, and in U.S. Patent ApplicationPublications 2002/0065455 A1, issued as U.S. Pat. No. 6,690,963 on Feb.10, 2004; 2003/0120150 A1 issued as U.S. Pat. No. 7,729,742 on Jun. 1,2010, and 2004/0068178 A1, now abandoned.

Processing circuitry 41, typically part of a general-purpose computer,is further connected via a suitable front end and interface circuits 44,to receive signals from body surface-electrodes 49. Processing circuitry41 is connected to body surface-electrodes 49 by wires running through acable 39 to the chest of patient 28.

In an embodiment, processing circuitry 41 renders to a display 27, arepresentation 31 of at least a part of the catheter 40 and a mappedbody-part, responsively to computed position coordinates of the catheter40.

Processing circuitry 41 is typically programmed in software to carry outthe functions described herein. The software may be downloaded to thecomputer in electronic form, over a network, for example, or it may,alternatively or additionally, be provided and/or stored onnon-transitory tangible media, such as magnetic, optical, or electronicmemory.

The medical system 20 may also include an ablation power generator 69(such as an RF signal generator) configured to be connected to thecatheter 40, and apply an electrical signal to the electrodes 48. Themedical system 20 may also include an irrigation reservoir 71 configuredto store irrigation fluid, and a pump 73 configured to be connected tothe irrigation reservoir 71 and the catheter 40, and to pump theirrigation fluid from the irrigation reservoir 71 through irrigationholes of an irrigation tube of the catheter 40 as described in moredetail with reference to FIGS. 2 and 3 .

The example illustration shown in FIG. 1 is chosen purely for the sakeof conceptual clarity. FIG. 1 shows only elements related to thedisclosed techniques for the sake of simplicity and clarity. System 20typically comprises additional modules and elements that are notdirectly related to the disclosed techniques, and thus are intentionallyomitted from FIG. 1 and from the corresponding description. The elementsof system 20 and the methods described herein may be further applied,for example, to control an ablation of tissue of heart 26.

Reference is now made to FIGS. 2 and 3 . FIG. 2 is a schematic view ofthe catheter 40 in a collapsed form constructed and operative inaccordance with an embodiment of the present invention. FIG. 3 is aschematic view of the catheter 40 of FIG. 2 in a deployed expanded form.

The catheter 40 is configured to be inserted into a body part (e.g., theheart 26 (FIG. 1 )) of a living subject. The deflectable element 22 ofthe catheter 40 has a distal end 33. The deflectable element 22 may beproduced from any suitable material, for example, polyurethane orpolyether block amide. The assembly 35 is disposed distally to thedeflectable element 22 and may be connected to the deflectable element22 via a proximal coupling member 50 at the distal end 33. The proximalcoupling member 50 typically comprises a hollow tube and may be formedfrom any suitable material, for example, but not limited topolycarbonate with or without glass filler, polyether ether ketone(PEEK) with or without glass filler, polyimide, polyamide, orPolyetherimide (PEI) with or without glass filler. The coupling member50 may formed as an integral part of the deflectable element 22 or aspart of the distal end assembly 35 or as a separate element whichconnects with the deflectable element 22 and the distal end assembly 35.

The assembly 35, which may include a basket assembly, may includemultiple splines such as flexible strips 55 (only one labeled for thesake of simplicity). In the embodiments of FIGS. 2 and 3 each flexiblestrip 55 includes a single electrode 48 (only some labeled for the sakeof simplicity). The assembly 35 may include any suitable number ofelectrodes 48 with multiple electrodes 48 per strip 55.

In the embodiment of FIGS. 2 and 3 , each flexible strip 55 is formed ofNitinol which is selectively covered with insulating material in thedistal and proximal regions 57 (only some labeled for the sake ofsimplicity) of the flexible strips 55 leaving a central region 59 (onlysome labeled for the sake of simplicity) of the flexible strips 55 as anelectrically active region to perform mapping and/or perform ablation orelectroporation, by way of example. The structure of the assembly 35 mayvary. For example, flexible strips 55 (or other splines) may includeflexible printed circuit boards (PCBs), or a shape-memory alloy such asNitinol.

Embodiments described herein refer mainly to a basket distal-endassembly 35, purely by way of example. In alternative embodiments, thedisclosed techniques can be used with any other suitable type ofdistal-end assembly.

The distal end assembly 35 includes a distal portion 61, and a proximalportion 63, and is configured to expand from a collapsed form (shown inFIG. 2 ) to an expanded deployed form (shown in FIG. 3 ).

The relaxed state of the distal end assembly 35 is the expanded deployedform shown in FIG. 3 . The distal end assembly 35 is configured tocollapse into the collapsed form when the catheter 40 is retracted in asheath 23 (FIG. 1 ) and is configured to expand to the expanded deployedform when the catheter 40 is removed from the sheath 23. The relaxedshape of the distal end assembly 35 may be set by forming the flexiblestrips 55 from any suitable resilient material such as Nitinol or PEI.

The catheter 40 includes a stretchable irrigation tube 65 disposedbetween the distal portion 61 and the proximal portion 63. Thestretchable irrigation tube 65 includes a plurality of irrigation holes67 (only some labeled for the sake of simplicity), and is configured tostretch longitudinally when the distal end assembly 35 is collapsed fromthe expanded deployed form to the collapsed form. The stretchableirrigation tube 65 includes a biocompatible stretchable material, suchas Polyether block amide (PEBA) (e.g., PEBAX (with a shore D durometerbetween 25 and 72-55D)), or a stretchable Polyurethane, a siliconepolymer, or expanded Polytetrafluoroethylene (ePTFE). The stretchableirrigation tube 65 may have any suitable dimensions, for example, anouter diameter in the range of 0.5 mm to 3 mm, e.g., 1.5 mm, a wallthickness in the range of 0.01 mm to 0.5 mm, e.g., 0.125 mm. The holes67 may have any suitable diameter, for example, in the range ofapproximately 0.01 mm to approximately 0.2 mm, e.g. approximately 0.165mm. The tube 65 may include any suitable number of discrete holes, forexample, between 1 and 200, e.g. 50. The stretchable irrigation tube 65is shown in FIG. 3 as a transparent stretchable irrigation tube 65 forthe sake of clarity. Alternatively, the stretchable irrigation tube 65may be translucent or opaque or any suitable combination thereof. Thepump 73 (FIG. 1 ) is configured to pump irrigation fluid from theirrigation reservoir 71 through the irrigation holes 67 of theirrigation tube 65.

In some embodiments, the irrigation holes 67 are disposed radiallyaround the irrigation tube 65 and/or longitudinally along the irrigationtube 65. In other embodiments, the irrigation holes 67 can be disposedsuch that each hole 67 extends at an angle relative to the longitudinalaxis. In one embodiment, each hole may extend at an angle ofapproximately 90 degrees relative to the longitudinal axis L-L so thatthe hole is orthogonal with respect to the longitudinal axis L-L. Theorientations of the irrigation holes 67 are typically oriented (usuallynon-parallel to the longitudinal axis L-L) to ensure sufficient coverageof the electrodes with irrigation flow and therefore each irrigationhole 67 may not have the same orientation as its neighbor.

In some embodiments, the holes 67 may include laser or mechanicallydrilled holes. For example, laser drilled holes may be formed in thebiocompatible stretchable material, e.g., in PEBA. In some embodiments,the biocompatible stretchable material, e.g., ePTFE, is a porousmaterial that includes pores forming at least some of the holes 67.

Reference is now made to FIG. 4 is a cross-sectional view of thecatheter 40 of FIG. 3 along line A:A. FIG. 4 (inside block A) shows thedistal ends of the flexible strips 55 (only two labeled for the sake ofsimplicity) folded over and connected to a distal connector 75, which insome embodiments is a tube (e.g., polymer tube) or slug (e.g., polymerslug). The distal end of the stretchable irrigation tube 65 is connectedto the distal connector 75. The distal connector 75 is described in moredetail with reference to FIG. 5 .

In some embodiments, the flexible strips 55 may be connected to thedistal connector 75 without being folded over so that when the distalend assembly 35 is collapsed the flexible strips 55 are approaching aflat formation along their length.

FIG. 4 (inside block B) shows that the proximal ends of the flexiblestrips 55 are connected to the proximal coupling member 50. The proximalend of the stretchable irrigation tube 65 is connected to (e.g.,stretched over) a proximal connector 77 (for example, a polymer slug).The proximal connector 77 is described in more detail with reference toFIG. 6 . FIG. 4 also shows an irrigation line 79 (which extends throughthe deflectable element 22, the proximal coupling member 50, and a slot83 in the proximal connector 77) and a position sensor 81 (e.g., amagnetic position sensor).

Reference is now made to FIG. 5 is a more detailed cross-sectional viewof the catheter 40 inside block A of FIG. 4 . The distal end of thestretchable irrigation tube 65 is connected to the distal connector 75.The flexible strips 55 are secured between the stretchable irrigationtube 65 and a distal securing ring 85. An adhesive or epoxy layer 86 isdisposed between the distal securing ring 85 and the flexible strips 55thereby securing the securing ring 85 to the flexible strips 55. Thestretchable irrigation tube 65 and the flexible strips 55 may be securedusing pressure and/or any suitable adhesive. The distal connector 75 andthe distal securing ring 85 may be formed from any suitable material,for example, but not limited to polycarbonate with or without glassfiller, PEEK with or without glass filler, or PEI with or without glassfiller. The distal connector 75 also functions as a slug to plug thedistal end of the stretchable irrigation tube 65.

Reference is now made to FIG. 6 is a more detailed cross-sectional viewof the catheter 40 inside block B of FIG. 4 .

FIG. 6 shows the proximal connector 77 with the slot 83. The slot 83allows the irrigation line 79-3 and electrical wires (e.g., forconnection to one or more electrodes and/or sensors) to traverse theproximal connector 77. The irrigation line 79-2 connects to theirrigation line 79-3, which is narrower so that it fits in the slot 83.The stretchable irrigation tube 65 is connected to the proximalconnector 77 and is shown as being stretched over the proximal connector77. The stretchable irrigation tube 65 may be connected to the proximalconnector 77 using any suitable connection method. A proximal securingring 87 is disposed around the stretchable irrigation tube 65 to aidsecuring the stretchable irrigation tube 65 to the proximal connector77. The stretchable tube 65 in FIG. 6 is shown partially in an“unstretched” configuration, meaning that the tube 65 is not beingelongated along the longitudinal axis L-L (FIG. 7B). Irrigation holes 67are preferably in the form of a generally circular opening of a diameterof approximately 0.165 mm in the unstretched configuration of tube 65.

The proximal end of the flexible strips 55 are secured between theproximal coupling member 50 and the position sensor 81 and theirrigation line 79-2. Another securing ring 89 is secured over theproximal coupling member 50 to aid securing of the flexible strips 55 tothe proximal coupling member 50. The flexible strips 55 may be securedto the proximal coupling member 50 using pressure and/or any suitableadhesive.

The proximal connector 77, the proximal securing ring 87, and thesecuring ring 89 may be formed from any suitable material, for example,but not limited to polycarbonate with or without glass filler, PEEK withor without glass filler, or PEI with or without glass filler.

Reference is now made to FIGS. 7A and 7B. FIG. 7A is a schematic view ofa catheter 100 in a collapsed form constructed and operative inaccordance with an alternative embodiment of the present invention. FIG.7B is a schematic view of the catheter 100 of FIG. 7A in a deployed andexpanded form having a larger outer profile than the collapsed form ofcatheter 100. In the collapsed configuration of the basket catheter 100,tube 65 is in a “stretched” configuration (designated as elongated tube65′) that elongates tube by about 80% of the original unstretched lengthof tube 65 to arrive at the elongated tube 65′ being longer than theunstretched length of tube 65. In this configuration, it can be seen inthe inset of FIG. 7A of the elongated tube 65′ causes the circularirrigation holes 67 (of FIG. 6 ) to take on a slot like (i.e., roundedrectangular) perimeter 67′ of approximately 0.15 mm by 0.5 mm (e.g.,opening 67′ is approximately 250% increase in area of the originalopening 67) due to the elongation of tube 65′. In the expandedconfiguration of basket 100 shown in FIG. 7B, the tube 65 is not beingstretched along longitudinal axis L-L as shown by the inset schematicrepresentation of tube 65. In the unstretched tube configuration 65 forFIG. 7B, the irrigation holes 65 approximates a circular opening toallow irrigation fluid to flow through. In one embodiment, theunstretched length of tube 65 is approximately 6 mm and the elongatedlength 65′ (of the original tube 65) is approximately 11 mm.

The catheter 100 is substantially the same as the catheter 40 of FIGS.1-6 apart from the following differences. The relaxed state of thedistal end assembly 35 of the catheter 100 is the collapsed form of thedistal end assembly 35 shown in FIG. 7A, which relaxed state of thebasket 100 causes the stretching or elongation of the stretchable tube65′. The relaxed state may be configured by using a resilient material,for example, PEI or a shape-memory alloy such as Nitinol.

The catheter 100 includes a puller element 102 (e.g., a puller wire)disposed inside the deflectable element 22 and the stretchableirrigation tube 65, and connected to the distal portion 61 of the distalend assembly 35. The puller element 102 may be formed from any suitablematerial, for example, stainless steel, nitinol, and/orultra-high-molecular-weight polyethylene (UHMWPE). The puller element102 may have any suitable outer diameter, for example, in the range of0.05 mm to 0.5 mm, e.g., 0.175 mm. In some embodiments the pullerelement 102 is connected to the distal connector 75. The puller element102 is configured when pulled to expand the distal end assembly 35 fromthe collapsed form (shown in FIG. 7A) to the expanded deployed form(shown in FIG. 7B). The puller element 102 may be connected to themanipulator 32 (FIG. 1 ), which controls the puller element 102 todeploy the assembly 35 and change an ellipticity of the assembly 35according to the longitudinal displacement of the puller element 102with respect to the deflectable element 22.

As used herein, the terms “about” or “approximately” for any numericalvalues or ranges indicate a suitable dimensional tolerance that allowsthe part or collection of components to function for its intendedpurpose as described herein. More specifically, “about” or“approximately” may refer to the range of values ±20% of the recitedvalue, e.g. “about 90%” may refer to the range of values from 72% to108%.

Various features of the invention which are, for clarity, described inthe contexts of separate embodiments may also be provided in combinationin a single embodiment. Conversely, various features of the inventionwhich are, for brevity, described in the context of a single embodimentmay also be provided separately or in any suitable sub-combination.

The embodiments described above are cited by way of example, and thepresent invention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the invention includes bothcombinations and sub-combinations of the various features describedhereinabove, as well as variations and modifications thereof which wouldoccur to persons skilled in the art upon reading the foregoingdescription and which are not disclosed in the prior art.

What is claimed is:
 1. A medical device, the medical device comprising:a deflectable element extending along a longitudinal axis from aproximal end to a distal end; a distal end assembly disposed at thedistal end and comprising a proximal portion and a distal portion; anelectrode attached to the distal end assembly; and a stretchableirrigation element disposed between the proximal portion and the distalportion and comprising a plurality of irrigation holes, the stretchableirrigation element being attached to the distal portion.
 2. The medicaldevice of claim 1, the plurality of irrigation holes being disposed suchthat each irrigation hole of the plurality of irrigation holes extendsat an angle relative to the longitudinal axis.
 3. The medical device ofclaim 2, wherein an angle relative to the longitudinal axis of a firstirrigation hole of the plurality of irrigation holes is different thanan angle relative to the longitudinal axis of a second irrigation holeof the plurality of irrigation holes, the first irrigation hole beingadjacent the second irrigation hole.
 4. The medical device of claim 1,the plurality of irrigation holes being disposed radially around thestretchable irrigation element.
 5. The medical device of claim 1, theplurality of irrigation holes being disposed longitudinally along thestretchable irrigation element.
 6. The medical device of claim 1, theelectrode being configured for electro-anatomical mapping of an organ.7. The medical device of claim 1, the electrode being configured forablation of tissue of an organ.
 8. The medical device of claim 1, thedistal end assembly further comprising a spline configured to bowradially outward from the longitudinal axis, the electrode beingattached to the spline.
 9. The medical device of claim 1, the distal endassembly further comprising a plurality of splines extending between theproximal portion and the distal portion, the plurality of splinesconfigured to transition between a collapsed form and an expandeddeployed form.
 10. The medical device of claim 9, each spline of theplurality of splines comprising an electrode.
 11. The medical device ofclaim 10, wherein a relaxed state of the distal end assembly is theexpanded deployed form, the distal end assembly being configured tocollapse into the collapsed form when the distal end assembly isretracted in a sheath.
 12. The medical device of claim 10, wherein arelaxed state of the distal end assembly is the collapsed form, themedical device further comprising a puller element disposed inside thedistal end assembly and the stretchable irrigation element, andconnected to the distal portion of the distal end assembly, andconfigured when pulled to expand the distal end assembly from thecollapsed form to the expanded deployed form.
 13. The medical device ofclaim 9, each spline of the plurality of splines comprising Nitinol. 14.The medical device of claim 1, the stretchable irrigation elementcomprising a biocompatible stretchable material.
 15. The medical deviceof claim 1, further comprising a magnetic position sensor disposed atthe distal end of the deflectable element.
 16. A stretchable irrigationelement for a medical device, the stretchable irrigation elementcomprising: a tube extending along a longitudinal axis from a proximalend to a distal end, the proximal end configured for attachment to adeflectable element and the distal end configured for attachment to adistal portion of a basket catheter, the tube configured to be stretchedwhen a force is applied to the tube; and a plurality of irrigation holesdisposed longitudinally along the tube and configured to directirrigation fluid outwardly from the longitudinal axis toward electrodesof the basket catheter.
 17. The stretchable irrigation element of claim16, the plurality of irrigation holes being further disposed radiallyaround the tube.
 18. The stretchable irrigation element of claim 16, theplurality of irrigation holes being disposed such that each irrigationhole of the plurality of irrigation holes extends at an angle relativeto the longitudinal axis.
 19. The stretchable irrigation element ofclaim 18, wherein an angle relative to the longitudinal axis of a firstirrigation hole of the plurality of irrigation holes is different thanan angle relative to the longitudinal axis of a second irrigation holeof the plurality of irrigation holes, the first irrigation hole beingadjacent the second irrigation hole.
 20. The stretchable irrigationelement of claim 16, the stretchable irrigation element comprising abiocompatible stretchable material.